In which stage of the first meiotic division, each chromosome undergoes longitudinal division to give rise to two sister chromatids ?
Zygotene
Diplotene
Diakinesis
Pachytene
In biotic community, which of the following can be called protective device ?
Mimicry
Symbiosis
Competition
Parasitism
Which of the following enzymes is used to join bits of DNA?
Ligase
Primase
Endonuclease
DNA polymerase
A.
Ligase
Ligase is an enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.
Primase is an enzyme which is involved in the replication process of DNA. It is a type of RNA Polymerase. It catalyzes the synthesis of a short RNA segment called a primer complementary to a ssDNA template.
Nucleases are enzymes that cut, shorten or degrade nucleic acids. Endonucleases are enzymes which are able to break internal phosphodiester bonds within a DNA molecule.
DNA polymerases are enzymes that synthesize a new strand of DNA complementary to an existing DNA or RNA template.
All eukaryotic genes contain two kinds of base sequences. Which of the following plays role in protein synthesis ?
Introns
Exons
Electrons
Both (a) and (b)
The direction of DNA replication is from :
amino acid end
3' end towards 5' end
5' end towards 3' end
amino terminus to carboxy terminus
Mirabilis jalapa is an example of
complete dominance
supplementary gene
incomplete dominance
complementary gene
Which of the following is dominant character according to Mendel ?
Dwarf plant and yellow fruit
Terminal fruit and wrinkled seed
White testa and yellow pericarp
Green coloured fruit and rounded seed
Lack of independent assortment of genes A and B in fruit fly Drosophila is due to :
repulsion
linkage
crossing-over
recombination
When two mutations are located in the same functional unit or in different functional units, then it is confirmed by :
test cross
back cross
reciprocal cross
complementation test